I've been curious about the real behavior of fires inside a spaceship in zero gravity. We've seen all sorts of variations in movies. Most of those feel bogus to me because there should not be much in the way of flammable substances inside a ship, aside from flammable or toxic gasses in some plumbing.

Ah, but what should be and what is are often two different things. Apollo 1 is a case in point where there were flammable materials, and wasn't there a Russian Mir that had a fire or almost did due to not being maintained properly or something.